<form action="<?php echo $this->url(array('module'=>'admin', 'controller'=> 'comment', 'action'=>'add')); ?>" method="post">
    <table>
       <tr>
            <th>Comment Content:</th>
       </tr>

       <textarea name="comment" cols="40" rows="5"></textarea>

       <tr><td/><td><input type="submit" name="submit" value="  Update  " /></td></tr>
    </table>
</form>